/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Public/GameplayEffectTypes.h
Broadcasts the AnyChange event for this tag. This is called when the stack count of the backing gameplay effect change. It is up to the receiver of the broadcasted delegate to decide what to do with this.
void Notify_StackCountChange ( const [FGameplayTag](API\Runtime\GameplayTags\FGameplayTag) & Tag )